Two-Temperature Magnetohydrodynamics Simulations of Propagation of Semi-Relativistic Jets
In astrophysical jets observed in active galactic nuclei and in microquasars, the energy exchange rate by Coulomb collision is insufficient for thermal equilibrium between ions and electrons. Therefore, it is necessary to consider the difference between the ion temperature and the electron temperatu...
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| Format: | Article |
| Language: | English |
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MDPI AG
2019-01-01
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| Series: | Galaxies |
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| Online Access: | http://www.mdpi.com/2075-4434/7/1/14 |
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| author | Takumi Ohmura Mami Machida Kenji Nakamura Yuki Kudoh Yuta Asahina Ryoji Matsumoto |
| author_facet | Takumi Ohmura Mami Machida Kenji Nakamura Yuki Kudoh Yuta Asahina Ryoji Matsumoto |
| author_sort | Takumi Ohmura |
| collection | DOAJ |
| description | In astrophysical jets observed in active galactic nuclei and in microquasars, the energy exchange rate by Coulomb collision is insufficient for thermal equilibrium between ions and electrons. Therefore, it is necessary to consider the difference between the ion temperature and the electron temperature. We present the results of two-temperature magnetohydrodynamics(MHD) simulations to demonstrate the effects of Coulomb coupling. It is assumed that the thermal dissipation heats only ions. We find that the ion and electron temperatures are separated through shocks. Since the ion entropy is increased by energy dissipation at shocks and the Coulomb collisions are inefficient, electron temperature becomes about 10 times lower than the ion temperature in the hotspot ahead of the jet terminal shock. In the cocoon, electron temperature decreases by gas mixing between high temperature cocoon gas and low temperature shocked-ambient gas even when we neglect radiative cooling, but electrons can be heated through collisions with ions. Radiation intensity maps are produced by post processing numerical results. Distributions of the thermal bremsstrahlung radiation computed from electron temperature have bright filament and cavity around the jet terminal shock. |
| first_indexed | 2024-12-12T01:54:00Z |
| format | Article |
| id | doaj.art-cf1b01e3831f46c8b718ffb4a0e7340d |
| institution | Directory Open Access Journal |
| issn | 2075-4434 |
| language | English |
| last_indexed | 2024-12-12T01:54:00Z |
| publishDate | 2019-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Galaxies |
| spelling | doaj.art-cf1b01e3831f46c8b718ffb4a0e7340d2022-12-22T00:42:25ZengMDPI AGGalaxies2075-44342019-01-01711410.3390/galaxies7010014galaxies7010014Two-Temperature Magnetohydrodynamics Simulations of Propagation of Semi-Relativistic JetsTakumi Ohmura0Mami Machida1Kenji Nakamura2Yuki Kudoh3Yuta Asahina4Ryoji Matsumoto5Graduate School of Science, Kyushu University, 744 Motooka Nishi-ku, Fukuoka 819-0395, JapanGraduate School of Science, Kyushu University, 744 Motooka Nishi-ku, Fukuoka 819-0395, JapanDepartment of Mechanics, Faculty of Science and Technology, Kyushu Sangyo University, 2-3-1 Matsukadai, Higashi-ku, Fukuoka 813-8503, JapanGraduate School of Science and Engineering, Kagoshima University, Kagoshima 890-0065, JapanYukawa Institute for Theoretical Physics, Kyoto University Kitashirakawa Oiwakecho, Sakyo-ku, Kyoto 606-8502, JapanDepartment of Physics, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, JapanIn astrophysical jets observed in active galactic nuclei and in microquasars, the energy exchange rate by Coulomb collision is insufficient for thermal equilibrium between ions and electrons. Therefore, it is necessary to consider the difference between the ion temperature and the electron temperature. We present the results of two-temperature magnetohydrodynamics(MHD) simulations to demonstrate the effects of Coulomb coupling. It is assumed that the thermal dissipation heats only ions. We find that the ion and electron temperatures are separated through shocks. Since the ion entropy is increased by energy dissipation at shocks and the Coulomb collisions are inefficient, electron temperature becomes about 10 times lower than the ion temperature in the hotspot ahead of the jet terminal shock. In the cocoon, electron temperature decreases by gas mixing between high temperature cocoon gas and low temperature shocked-ambient gas even when we neglect radiative cooling, but electrons can be heated through collisions with ions. Radiation intensity maps are produced by post processing numerical results. Distributions of the thermal bremsstrahlung radiation computed from electron temperature have bright filament and cavity around the jet terminal shock.http://www.mdpi.com/2075-4434/7/1/14astrophysical jetsmagnetohydrodynamics (MHD)numerical simulation |
| spellingShingle | Takumi Ohmura Mami Machida Kenji Nakamura Yuki Kudoh Yuta Asahina Ryoji Matsumoto Two-Temperature Magnetohydrodynamics Simulations of Propagation of Semi-Relativistic Jets Galaxies astrophysical jets magnetohydrodynamics (MHD) numerical simulation |
| title | Two-Temperature Magnetohydrodynamics Simulations of Propagation of Semi-Relativistic Jets |
| title_full | Two-Temperature Magnetohydrodynamics Simulations of Propagation of Semi-Relativistic Jets |
| title_fullStr | Two-Temperature Magnetohydrodynamics Simulations of Propagation of Semi-Relativistic Jets |
| title_full_unstemmed | Two-Temperature Magnetohydrodynamics Simulations of Propagation of Semi-Relativistic Jets |
| title_short | Two-Temperature Magnetohydrodynamics Simulations of Propagation of Semi-Relativistic Jets |
| title_sort | two temperature magnetohydrodynamics simulations of propagation of semi relativistic jets |
| topic | astrophysical jets magnetohydrodynamics (MHD) numerical simulation |
| url | http://www.mdpi.com/2075-4434/7/1/14 |
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